Contents

The story opens when Tyler Dupree is twelve years old. Tyler and his mother live in a guest house on the property of aerospace millionaire E.D. Lawton and his alcoholic wife Carol. Tyler is friends with the couple's fourteen-year-old twins Jason, a brilliant student who is being groomed to take over the family business, and Diane, with whom Tyler is in love. One night while stargazing, the three children witness all the stars simultaneously disappear. Telecommunications suffer as every satellite falls out of orbit simultaneously. Attempts to communicate with the ISS are unsuccessful.

It turns out that an opaque black membrane, later dubbed a "spin membrane" has been placed around the entire earth. Eventually it is determined that the membrane has slowed down time so that approximately 3.17 years pass outside the membrane for every second within, or, in a more cosmic scale, 100 million years on the outside for every year within. The membrane is permeable to spacecraft, but protects the earth from the harmful effects of concentrated stellar radiation and cometary impact. A simulated sun on the inside of the membrane allows for a largely normal life cycle to continue on earth. However, the greatly increased passage of time outside the membrane means that all life on earth will end in a few decades when the sun's expansion makes that region of the solar system uninhabitable. The membrane is apparently being controlled by a pair of city sized objects floating over both of Earth's poles. A Chinese attack on the devices using nuclear weapons causes a brief visual disturbance of the membrane but not change in the time dilation and other attempts to interfere with it are called off. Meanwhile, Diane and Jason diverge paths, as Jason becomes obsessed with gaining knowledge about the membrane and how to deactivate it, while Diane joins a growing quasi-religious movement, called the NK, or "New Kingdom". The NK movement, a sect of Christianity that endorses hedonism and indulgence, quickly gains ground among Diane's generation.

In the wake of what becomes known as "the Spin", Jason studies science and joins his father at Perihelion, an aerospace research firm which eventually gets folded into the government and coordinates efforts to deal with the Spin. Tyler attends medical school and becomes a doctor, while Diane marries a man named Simon, whom she met through the NK movement.

Jason eventually rises to run the day-to-day operations of Perihelion and hires Tyler as staff physician. Jason explains that Perihelion intends to terraformMars by releasing bacteria and plant seeds to change the habitat into one that is survivable by humans. Because of time dilation this process, which will occur over millions of years, will be finished in a few months of subjective Earth time. When the terraforming is complete, Perihelion and its counterparts in other nations launch manned colonization missions to Mars. While months pass on Earth these colonists will have hundreds of thousands of years to build a Martian civilization and possibly discover more about the Spin and the alien Hypotheticals responsible for it. A mere two years after the terraforming process begins, they receive satellite images confirming the existence of agriculture and sophisticated human civilizations on Mars. Soon afterwards Mars is enclosed in its own Spin membrane.

Eventually, the NK movement fades from culture, as the appeal of public nudity and casual sex wears off and some of the original members die from AIDS or spiral into drug addictions. Diane and Simon move to Phoenix, where Simon gets a janitorial position at a local church, and Diane secretly calls Tyler on rare occasions when Simon is busy.

Before the membrane went up the Martians sent their own manned mission to Earth. The Martian ambassador, Wun Ngo Wen, is part of a civilization hundreds of thousands of years old which has been experimenting with high end biotechnology for centuries. Jason, who has developed an acute form of multiple sclerosis which is incurable by terrestrial medicine, takes a Martian bioengineering product which extends his life by decades, putting him into a fourth stage of life past adulthood. Jason and Wun Ngo Wen then intend to seed nanotechnology through the outer solar system. This technology will eventually expand to other star systems over the course of millions of years and search for other worlds enclosed by Spin membranes, hopefully discovering why they were created and if anything can be done to stop them. Wun Ngo Wen is eventually killed by extremists (the exact motive is never stated, but possibilities are listed) while returning from touring the Grand Canyon. However, the plan moves ahead, and Wun's memory lives on.

Tyler leaves Perihelion after being betrayed by his girlfriend, and moves to California. There he gets a desperate call from Simon, stating that Diane is terribly sick. Diane and Simon had moved from the ashes of the NK movement to join a more cult-like fringe movement which was trying to hasten the second coming through genetic engineering of cattle. As Tyler heads to meet Diane the Spin membrane seems to falter and fail, allowing the stars to return to the sky. The next day, the sun rises huge and red in the sky causing terrible heat and high winds. Millions across the world panic as the apparent end has come. Tyler finds Diane suffering from a fatal cardiovascular disease, called CVWS, which crossed from cows to humans during the attempts to breed a totally red calf. The only cure is to give her the same treatment that Jason has taken. He and Simon drive Diane back to Diane's childhood home where Tyler had hidden some of the biotech along with notes from Wun Ngo Wen. Simon, however, leaves Tyler and Diane and gives them his blessing, and is never seen again. Tyler discovers that Jason is at the house, dying of a mysterious ailment. Jason explains that he has become a human receiver for the nanotechnology which they have seeded throughout the galaxy. He also explains his conclusions about the nature of the Hypotheticals and the Spin. The Hypotheticals are intelligent von neumann machines which were spread throughout the galaxy billions of years previously. Horrified at the rise and fall of biological societies they saw around them they devised a plan whereby they would enclose planets on the verge of societal collapse in Spin membranes to slow their advancement until a way could be found to save them. Jason dies shortly after explaining this and has Tyler mail copies of the information to trusted informants.

Tyler gives the Martian treatment to Diane, who recovers. Shortly after the membrane partially reasserts itself, allowing the stars to be seen, and synchronizing earth time with that of the universe, but filtering the solar radiation to a survivable level. It's discovered that the Spin membrane had been retracted in order to let a massive ring shaped object descend and embed itself in the Indian Ocean. The "Arch", as it becomes known, acts as a portal to another world, one engineered by the Hypotheticals to give mankind a new chance at life. A decade after the appearance of the Arch, Diane and Tyler, now married, flee from agents of the US government who seek to arrest them for possessing forbidden Martian technology. Tyler takes the same cure that Jason and Diane Lawton did, becoming a "Fourth" himself, and Tyler and Diane pass through the Arch with a group of Indonesian refugees. They scatter Jason's ashes right in the crossing between Earth and the other world, so that he finally can be at peace.

The setting is Earth, after the planet is enclosed by a "spin membrane." The membrane blocks out the stars, rendering the night sky completely black. A normal night-day cycle is maintained by an artificial image of the sun on the interior of the membrane. This image is indistinguishable from the real sun to the casual observer, but scientific measurements determine that it presents a completely regular aspect without the sunspots, solar flares, or other changes which accompany the real sun. The membrane is controlled and maintained by two city sized alien objects hovering above Earth's poles. The aliens responsible for the spin are nicknamed "Hypotheticals".

Other than obscuring the stars, the other immediate impact of the membrane is damage to telecommunications since every satellite orbiting Earth crashes to the ground that first night. A manned space craft orbiting Earth is caught outside the membrane and spends two weeks orbiting before deciding to try and land. Upon doing so, the astronauts are informed that they have been aloft for less than a day. It is eventually determined that the spin membrane slows down time on Earth. Eventually the rate is calculated, with approximately 3.7 years passing outside the membrane for every second inside. The membrane is permeable to spaceships and other man made objects, but protects the planet from the harmful effects of condensed cometary impact and concentrated stellar radiation. Because of the time dilation, orbital satellites are no longer useful, since any orbital object will fall to earth in a few subjective minutes after launch. Instead, high altitude aerostats are used to restore telecommunications.

While life initially goes on largely as before, scientists determine that the greatly increased flow of time outside the membrane will mean that the sun's evolution to its red giant phase will render the Earth's region of the solar system uninhabitable within a few decades. It is unknown if the spin membrane will protect Earth from such an event, although most presume that it will not. This news is met with differing reactions. Many initially seek refuge in chiliastic religion, although interest in this fades after a few years. The Spin also sees rising crime rates with highway robbery becoming increasingly common.

The time dilation of the spin allows for some large scale projects which would have been politically or logistically impossible before. The first of these is the terraforming of Mars. This is conducted using a two-stage launch first of bacteria and then of plants, designed to change the Martian landscape into one survivable by humans. After only a few months of subjective Earth time, the plan succeeds and Mars has a breathable atmosphere and plant life. Human settlers are sent on a fleet of rockets. Two subjective Earth years later, observation shows evidence of agriculture on Mars.

The Martians are short and long-limbed with dark wrinkly skin. By the time of the arrival of Martian ambassador Wun Ngo Wen, their civilization is hundreds of thousands of years old. While the Martians had historical records of Earth, they refrained from returning to their world of origin or probing the spin membrane for fear of attracting the attention of the Hypotheticals. Their approach changed when they detected spin devices under automated construction above Mars poles. Soon after, Mars is enclosed in its own Spin membrane. As a low energy world, Mars relied on a much more controlled society on Earth, and had been using advanced biotechnology for centuries in order to maximize efficiency. However, their society, which was dependent on nitrogen, was also nearing a breaking point when the spin membrane enclosed Mars.

One aspect of a Martian biotechnology is a treatment which rewrites the patient's genetic code, curing most diseases and extending the patient's life by decades. This is considered a fourth stage of life, beyond adulthood. Fourths, as recipients are known, are unusually perceptive and compassionate towards other people. The treatment also allows for the addition of other biotechnological enhancements, allowing the Fourth to do unusual things. Jason Lawton receives an upgrade which allows him to communicate with mechanical probes about to be sent out into the universe, although the treatment eventually proves fatal.

These probes are another example of the large scale projects that the spin allows humans to conduct. Seeded throughout the outer solar system, these self-replicating probes spread out and observe the solar system. They then move out into the wider galaxy. This process takes millions of years, but for those on Earth only a few years pass due to the time differential across the spin. The goal of the probes was to seek out and investigate other worlds enclosed by spin membranes. Eventually the probes encounter several "optically black" worlds in other solar systems. They also encounter other, alien, probes in interstellar space. Jason Lawton concludes that these probes were seeded throughout the galaxy billions of years ago by parties unknown. Left to their own devices they have developed into an unusual ecosystem, with some, The Hypotheticals, developing sentience. The Hypotheticals grew increasingly horrified at a cycle which they saw where organic beings inevitably created civilizations which eventually used up the material resources of their homeworlds. The Hypotheticals, who by this point had gained the ability to manipulate time itself, used the spin membranes to slow down the development of worlds on the brink of ecological collapse. This slow down would allow the Hypotheticals time to implement a solution.

The solution for Earth is a giant ring, called The Arch, which the Hypotheticals transport to Earth and bury halfway in the Indian Ocean. Bringing the Arch to earth requires the Hypotheticals to temporarily lower the spin membrane. After the Arch is in place, the membrane reasserts itself but with changed settings. This new membrane synchronizes Earth time to that of the universe and allows the stars to be seen once again. However, it also filters the light of the sun to survivable levels.

The Arch itself functions as a gateway. Traversing it in a specific direction allows people to cross over to a new ecologically fresh world.